Research is proposed to determine the characteristics of gaze produced by head and eye movements during angular locomotion in humans. Normal human subjects will walk or run on a circular treadmill. Their eye movements will be recorded in three dimensions with a video technique and head and body movements with optical methods. It will be determined whether gaze is stabilized in space during angular locomotion, whether the head and eyes both contribute to gaze stabilization, whether the time constant of the aVOR is prolonged by the somatosensory input during angular walking, and whether gaze is spatially oriented to the tilt of gravio-inertial acceleration produced by the centripetal linear acceleration during angular locomotion. Studies will also be done to determine how gaze stabilization during angular locomotion compares to that during tangential centrifugation while standing and during walking in place. It will be determined how the angular VOR (aVOR) is adapted by prolonged walking and how orientation of gaze is disrupted by the absence of velocity storage. Critical parameters that cause adaptation of vestibular time constants during angular walking will be determined. Based on studies in the monkey, it is predicted that the head and eyes of humans will contribute to compensatory gaze nystagmus as angular locomotion rates rise. It is also predicted that gaze velocity in space (Gs), which is the sum of eye in head (Eh) and head on body (Hb) velocity will orient with the trunk to the vector of gravito-inertial acceleration to maintain balance, regardless of the speed of angular walking. It is anticipated that a loss of velocity storage will be associated with a reduction in balance capability, measured by the goodness of alignment of the body vertical to gravito-inertial acceleration. Through a study of how vision, linear acceleration and the somatosensory system affect gaze, this research should give new understanding to the functional role of velocity storage in supporting gaze during locomotion.